Alarm system for heat exchange devices



13. 21, 1948. H, mm 2,457,069

ALARM SYSTEM FOR HEAT EXCHANGE DEVICES Filed Feb. 5. 1 945 Patented Dec. 21, 1948 ALARM SYSTEM FOR HEAT EXCHANGE DEVICES Herbert H. Ranh, Columbus, Ohio, asslgnor to Ranoo Incorporated, Columbus, Ohio, a corporation of Ohio Application February 5, 1945, Serial No. 510,290

The present invention relates to a control system for a heat exchange device such as a refrigerator. Heat exchange devices are. usually automatically operated and at times are overloaded. Also, the automatic control mechanism may fail to operate. a

One of the objects of the present invention is to provide a signal which will warn the user of the device of an abnormal condition of the device, such as, for example, an overloaded condition 6 Claims. (Cl. 177311) on the device or a failure of the automatic controlling mechanism.

In the event of an overload condition, the heat exchange can be continued, however the signal may be annoying and, therefore, it is a further object of the present invention tov manually discontinue the signal, yet provide for conditioning the signal for recurrent operation in the event of another abnormal condition such as overloading the heat exchange device, or the failure of the automatic control.-

A heat exchange device usually employs a current consuming element, such as an electric motor, and such element is usually intermittently energized to operate the exchange device; It is still another object of the present invention to concurrently recondition the signal for operation, if it had been previously rendered ineffective manually, through the controller for the element.

Another object of the invention'is to provide a circuit controller in which the movable contact is biased to either its open or closed position, for

example, by a spring, which contact can be moved at will from its closed position to open position. And, in furtherance of this object, it is still another object to utilize an electromagnet, which is intermittently energized, for moving the contact from its open to its closed position.

Further objects and. advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Fig. l is a diagrammatic view of one form of the control system applied to a heat exchange device, the device shown being a mechanical refrigerator; and

Fig. 2 is a view of one of the controllers shown in Fig. 1, but showing same with the armature in a different position and showing parts thereof in cross section.

Referring to the drawings, an electrically operated signal 28 in the form of a bell is connected in a signal circuit which is energized by a source of current, herein shown as a battery ii. The signal circuit includes battery 2i, wire 22, movable contact 23, either of'contacts 25 or 28, wire 31, stationary and movable contacts 28 and 28, post 38, wire 3|, signal 20 and wire 32.

Movable contact 28 forms a part ofa controller 35. This controller 35 includes a base 33 which carries the post 38. A V notch 31 (see Fig. 2) in the post forms a socket type pivot for a lever 38; this lever is formed of metal and includes spaced branches 48, one being disposed at the front and the other at the back of the post. An end yoke 4i connecting the branches -48 rests for pivotal movement in the V notch 31. The branches to merge at 42 on the side of the post opposite the V notch 31. Contact 23 is carried by the lever 38. Alternate upwardly and downwardly extending projections 44 and 45 are formed on the lever 38 adjacent the merging portion 42 to form a pivotal socket 46 for one end 41 of a leaf spring 48. The other end 49 of the leaf spring is disposed in a V notch 50 in post 30. The positions of the notches 31 and 50 and socket 46 are such as to bias the lever either in a contact closing position, as shown in Fig. 1, or in a contact open position, as shown inFig. 2, i. e. the leaf spring may buckle in either direction and the lever will be resiliently maintained in either position to which it is moved. The statonary contact 28 limits the downward movement of lever 38 and a suitable stop 52 limits the upward movement of the lever.

An electromagnet 54 is carried on the top side of base 36 below the lever 38 and an armature 55 is carried by the lever 38 in cooperative relation with the magnet 54; If the lever 38 is in its open circuit position, as shown in Fig. 2, the armature 55 will be attracted when the electromagnet 54 is energized. This will cause the lever '38 to be snapped from its open circuit position to its closed circuit position. The leaf spring 48 then functions to yieldingly hold the lever 38 in its closed I circuit position.

The lever 38 can be moved manually from position shown in Fig. 1 to the position shown in Fig. 2 by a push rod 51. Rod 51 extends through and is guided by the base 35 and a bracket 58 carried by the base. A collar 59 is fastened to the rod 51 above the base 36 which collar is adapted to abut the top side of the base to limit the downward movement of the rod. A coil spring 68 surrounds rod 51 and is interposed between the collar 59 and bracket 58 for returning the rod to its retracted position. The rod 51 can be moved upwardly, manually, a sufficient distance to efiect cuit switch contacts I4 and I5.

reverse buckling of leaf spring 48 so that the lever 38 willibe biased by the spring B8 to its open circuit position.

The electromagnet 54 is intermittently energized and deenergized and is herein shown as being energized concurrently with a current cousuming element of the device which is to be controlled. The element is herein shown as an electric motor 62 of the type having a starting winding 63 and a running windin 64. The starting winding 63 of the motor 62 is interrupted by a motor starting relay 6B. The relay 68 may be of the type shown in the patent to E. C. Raney No. 2,304,018, issued December 1, 1942. The relay 68 includes abase 61 formed of dielectric material. A metal bracket 68 is suitably secured at one end thereof to the base 61, and one end thereof is connected to a terminal 69. A bimetallic strip II has one end thereof I2 secured to the underside of bracket 68. The other end of strip 1| carries a contact 14. Contact I4 is arranged to engage a contact I5 which is carried-by the free end of a second bimetallic strip 16. The other end of strip I6 is anchored to a post I8. Contact I5 is connected by a resilient conductor I9 to a terminal 80. Metallic post I8 is connected by a heating coil 8! toa terminal post 82.

Starting Winding 63 is connected bya wire 84 to a condenser 85 which, in turn, is connected to terminal 69 by wire 86. The running winding 68 of the motor is connected by a wire 81 to the terminal 82. Terminal 80 is connected to oneof the mains 89 by a wire 90. The circuit to the running winding of the motor is traced as follows: main 89, wire 98, terminal 80, conductor 79, contact 15, bimetallic strip I5, post 13, heating coil BI, terminal 82, wire at, motor winding 6e, wire 95, stationary contact 92, movable contact 93, stationary contact as, wire 95 and the other main 9%. The circuit for the starting'winding 53 is traced from the terminal 80 as follows: Conductor 79, contacts 75 and Id, bimetallic strip II, bracket I58, terminal 69, wire 85, condenser 85, wire til, winding 65 to wire 9i which. as previously explained, is connected to the main 9%. The starting winding will remain in circuit until the motor has attained its normal runnin speed.

The bimetallic strip it is proportioned so that the initial heavy flow of current through the circuit will heat the bimetal and cause the same to deflect downwardly and open the starting winding cir- This opening is effected in a short time equivalent to the time necessarily required for the motor to attain running speed. The flow of current through the.

strip it, during normal running of the motor, will not heat the strip suficiently to maintain the starting switch open during the .running of the motor. The heater 8|, however, is proportioned so that it is heated sufficiently by the flow of current through the motor, during normal operation thereof, to heat the strip It for maintaining the starting switch open.

The electromagnetic coil as is connected in parallel with the starting winding 03 of the motor s2 by wires 98 and 99, wire 98 bein connected to wire 88 and wire 59 being connected to wire 9|. Thus, it will be seen that when the motor is started, electromagnetic coil will be energized. and, the circuit thereto will be interrupted simultaneously with the interruption of the starting winding circuit. As previously stated, if the switch is in the position shown in Fig. 2, it will be moved to the position shown-in Fig. 1 when the motor 52 is started.

The heat exchange device is illustrated as a; mechanical refrigerator in whichthe compressor connected by a pipe II2 to a pressure reducing element II! and this element H3 in turn is connected by a pipe I14 to the evaporator. When the compressor II" is in operation. gaseous refrigerant is withdrawn from the evaporator I06 through the pipe H0. The compressed refrigerant is forced Into the condenser III where it is liquefied and the liquid refrigerant is then conducted to the evaporator through the pressure reducing element H3.

In order to maintain the desired temperature in the compartment. I01, the refrigerator is operated intermittently, that is, the refrigerator compressor is stopped when the temperature of the compartment attains a predetermined low value and is restarted when the compartment attains a predetermined high temperature. In order to accomplish this, there is provided a controller H6 which includes the contacts 92, 93 and 94. The controller is actuated by the expansion and contraction of volatile fluid contained in a thermostatic system. The system includes the tube II'I having one end II 8 thereof terminating within the compartment I91. The other end of the tube is connected with the interior of a contractable and expansible cell 9. When the temperature of the compartment increases, the pressure within the thermostatic system increases causing the expansion of cell lid, and when the temperature of the compartment is decreased, the pressure in the thermostatic system decreases-causing a contraction of the cell I 89.

The controller includes a lever I2I which is pivotally mounted at I22. The bottom side of one arm I23 of the lever I 2! is engaged by a pivot' movable contact 93. One end of coil spring I33 is connected to the lever I32 and the other end is connected to the arm I30 ofthe lever I2 I. The

, connections of the ends of the spring I33 with the lever I32 and the arm I30 and the position of the pivotal point of the lever I 32, are such that the spring tends to resiliently hold the lever I32 in the switch opening position or switch closing position, depending upon the position of the lever IZI. The contacts 92 and 94 form one of the stops for the lever I 32 and another stop is provided and indicated at I35.

.From the foregoing, it will be seen when the temperature of the compartment attains a predetermined high value, the cell I I9 will expand sufliciently to cause the lever I32 to be moved with a snap action from its open contact position to its closed contact position to start the motor 62 and when the temperature of the compartment III'I attains a predetermined low value, the con- 5 tact 93 will be open with a snap action to interrupt the motor circuit.

Heat exchange devices are usually used by the inexperienced, and quite often, the devices are overloaded. In the case of the refrigerating system, the user may be careless, permitting the door to the compartment to be open for too long intervals or too much warm food may be placed in the compartment. These are often the conditions in grocery stores and butcher shops. It is desirable to warn the user of the overloaded condition imposed on the refrigerator. To accomplish this, the extended end of the arm I30 of the lever i2l of controller H6 is arranged to engage the movable contact 23. In the event the compartment i! attains a predetermined high value above that normally desired, the cell H will have expanded suiliciently to cause the lever lw to move contact 23 into engagement with contact 26. This will complete the signal nal circuit through said third switch in response thereto.

2. In a control system for a heat exchange device of the character described including a storage compartment and power operated means for circulating a fluid refrigerant to provide for cooling the compartment, in combination, a main circuit, previously described. The operation of the signal may be objectionable and to overcome this objection, the signal circuit can .be broken,

through the push rod 51, by separating contact 29 from contact 28. The lever 38 will be retained in the circuit opening position by the buckled spring 48 until the next succeeding starting operation of the motor, at which time, the electromagnetic coil will be reenergized to again close contact 2@ with contact 28 so that the signal circuit will be reconditioned for operation for the next succeeding abnormal condition.

Another abnormal condition that'may occur is the leakage of thermostatic fluid from the thermostatic system, as for example, by the cracking of the flexible material of the cell I i9. When this occurs, little or no resistance will be offered to the spring I26 with the result that the lever i2i will be moved in a counterclockwise direction sufficiently to cause the movable contact 23 to engage contact to complete the signal circuit at this point.

From the foregoing, it will be seen that in addition to providing a signal for the failure of the controller lit, the control systemconditions the signal circuit for each cycle of operation so that the user is rewarned of an abnormal overload condition if he has manually disconnected the signal circuit.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow:

I claim:

1. In a control system for a heat exchange device of the character described including a storage compartment and power operated means for circulating a fluid refrigerant to provide for cooling the compartment, in combination, a mainv circuit supplying power to said power operated means, a main switch in said circuit for controlling the flow of power therein, an electrically responsive means energized when said switch is closed, a signal circuit including a switch actuated by said means, said signal circuit including a third switch, means operable in response to temperature changes at the upper and lower limits of a predetermined temperature range within the storage compartment to actuate the main switch, and said means also operably constructed to respond to temperature changes above and below the upper and lower limits respectively of said predetermined temperature ran e and close the sigcircuit supplying power to said power operated means, a main switch in said circuit for controlling the flow of power therein, an electrically responsive means energized when said switch is closed, a signal circuit including a switch actuated by said means, said signal circuit including a second switch means, means operable to actuate the main switch in response to temperature changes at the upper and lower limits of a predetermined temperature range within the storage compartment, and said means also operably constructed to respond to either temperature changes above or below the upper and lower limits respectively of said predetermined temperature range and to a failure of said temperature responsive means, to close the signal circuit through said second switch means.

3. In a control system for a heat exchange device of the character described including a storage compartment and power operated means for circulating a fluid refrigerant to provide for cooling the compartment, in combination, a signal circuit including a switch, means for biasing said switch either to an open or a closed position, electrical means for moving the switch from open position to closed position, said signal circuit including a second normally open switch means, a main switch supplying power to said power operated means, and means operable to actuate the main switch in response to temperature changes at the upper and lower limits of a predetermined temperature range within the storage compartment, and said means also operably constructed to respond to either an overload condition in said storage compartment wherein a temperature condition above said predetermined temperature range occurs or when a failure of said temperature responsive means occurs to close saidsecond switch in the signal circuit.

4. In a control system for a heat exchange device of the character described including a storage compartment, power operated means for'circulating a fluid refrigerant to provide for cooling the compartment, and employing an electrical current consuming element and an electrical circuit therefor to supply electric power to said power means, in combination, a main switch for said circuit controlling the flow of current therein, a second switch, means for biasing the second switch either to an open or to a closed position, electrical means energized when the main switch is closed for moving said second switch from the open to the closed position, means for moving the second switch to the open position, said biasing means being capable of holding the second switch in open position while the current flow is normal in the circuit for the current consuming element, a signal circuit including the second switch, and means having a pressure responsive 7 to close the signal circuit if the second switch is closed.

5. In a control system, a heat exchange device, a current consuming element for changing the temperature of the heat exchange device. a main circuit including the current consuming element, a main switch in said circuit, an electrically responsive meansenergized when said switch is closed, a signal circuit including a switch actuated by the electrically responsive means, a second switch in the signal circuit, means for controlling the opening and closing of the main switch to maintain the heat exchange device normaliy between predetermined high and low temperature limits, said last means including a thermostatic means responsive to the temperature or the heat exchange device and "connected with the main switch for actuating the same, said thermostatic means including mechanism for actuating the'second switch in the signal circuit when-the temperature of the heat exchange device is ab- 2 normal to one of its normal temperature limits. 6; In a control system, a heat'exchange device, a current consuming element for changing the temperature of the heat exchange device, a main 25 1 75 7 circuit including the current consuming element,

a main switch in said circuit, an electrically re-' sponsive means energized when said switch is closed, a signal circuit including a switch actuated by the electrically responsive means, a second switch in the signal circuit, means for controlling the opening and closing of the main switch to maintain the heat exchange device normally between predetermined high and low temperature limits, said last means including a thermostatic 35 2,418,068

means responsive to the temperature of the heat exchange device and connected with the main switch for actuating the same, said thermostatic means including mechanism for actuating the second switch in the signal circuit when the temperatureof the heat exchange device is abnormal to one of its normal temperature limits, means operable after the main circuit is closed for renderiiig the electrically responsive means inefiectlve to close the'first' mentioned switch in the signal circuit after said first mentioned switch is opened. and manual means for opening the first mentioned switch.

. mBERT H. RAUH.

REFERENCES (JITED The following references are of record in the file of this patent: 1 v

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